Smoke indicator device



i941. fHOMAs 2,244,507

SMOKE INDICATOR DEVICE Filed March 6, 1939 o 0 0 o VINVENTOR o o 0 flew 7/10 as; BYWAMM I ATTORNY Patented June 3, 1941 sMoxs mmoaroa DEVICE I t Henry Thomas; Elizabeth,N.J. g Application mm c, 1939, Serial No. 260,011 A; "(eras-14) 'f fiOlaims. I This invention frelates to smoke detector or indicator 'devices a'nd more particularly-to an One of the objectsl ofthe present invention is I to provide a simple and effective calibrating and adjusting means Ior'said devices. Anotherobje'ct-is to provide such a means which is operative by one unskilled in-the art. Still another -'object is to improve the operating efilciency of smoke detector and'indicator devices. Other obimproved method-and meansi'or calibrating and adjustingthesame. i

jects and advantages will be apparent as the invention ismore fully disclosed.

Smoke detector or indicator devices are utilized in the art as ameans for controlling the combustion conditions .within a furnace or'fire box whereby'moreemcient combustion oi. the fuel input to-the furnace, or fire box is obtained. In general such-devlcesflcomprlse aradiation sensitive means, a source 01' radiation and means to mount the radiation sensitive means and the source oi. radiation adjacent aligned openings in opposite sidesot a-smoke flue or chimney in such and condensation products by clouding up the lens means alter the operating characteristics or the said devices.

In operation, smoke detector devices record or indicate the loss of radiation incident to the density of the gases passing through the flue. with a perfectly clear flue, as when no combustion gases are circulating through the flue, the

radiation sensitive means receives and is actuated by the maximum ra'diationirom the source of radiation. As the-amount of smoke and gases of combustion increases the amount or radiation received by the radiation sensitive means decreases. Under any given Iumace or fire box conditions and withany given fuel, substantially perfect combustion of the fuel produces a determined flue gas density. It is possible to measure the carbon dioxide (CO2) content of the flue gases and to so correlate theradiation sensitive device readings with the carbon dioxide content that with any given readinga known carbon dioxide content is indicated,

manner that the radiation from the source will be projected through the openings onto the radiation sensitive means. The radiation sensitive means is connected in an electrical circuit to operate an electroresponsive means such as a recorder .device, an indicator device, an alarm system or means automatically regulating the fuel and air inputto the turnace orfire box or any combination or thesejinstrumentalities, as may be desired,,the said electrical circuit usually in- '1 eluding an'a'diustable means limiting energization of any control means 'associatedtherewith ito determined maximum and minimum limits or current intensities inithe said circuit.

" I- Itis essential in such an arrangement to maintain a substantially constant -voltage on the .source ot radiation and'in the circuit including I E the radiationasensitive means to obtain uniformly CODB tmtf QPEHflOD OI. the arrangement. It is customaryto-provide air vent openings be! I tween. the radiation sensitive means. and theflue' ,--and.bctween..thei source-ot radiation and the'iiue j to prevent the passage or smoke dust and-con- -'densa tionproductsinto .the housing inclosing theradiation sensitive means and the source of The carbon dioxide content or any flue gas is representative or the combustion conditions and in general it is desired to maintain a carbon dioxide content oi between 12 and,15% inthe flue gases as within this rangesubstantially perfect combustion conditions are maintained,-

Most smoke indicator orI'detector devices are provided therefore with means to record or to visually indicate whenfthe'fdensity or the hue gases rises or falls above or. below this range and for any given installation require trequent calibration, in situ, against a gas analysis device.

Suchcalibration requires the services otan expert operator and the use of special gas analysis equipment and the e p nse involved is prohibitive for small installations.

The present invention provides a simple and eflective means to obtain the calibration or smoke indicator devices to within any desired range of smoke densities representative or any desired CO: content in the flue gases, and also provides means to rapidly calibrate and adjust a smoke radiation thereby to prevent the deposit or dust and condensationproducts on the lens means utilized with the radiation ,sensitive means and the'source' '01 radiation to transmit radiation in "beam-form from the source-or'radiation (normfl r a lamp.) to the radiation sensitive means (normally a photosensitive devicela Such dust indicator device which does not require the services of an expert operator or the use or special sa's analysis-equipment,

In accordance with the objects or this invention I have devised a calibrating means which consists oi. a plurality ot-plates or sections, preferably but not necessarily assembled together substantially as shown in the drawing, each plate being comprised of suitable material having a translucency or opacity adapted to intercept a determined portion or percentage 01 light radiation in the beam being projected from the light source, the size, shape and configuration of the plate or section preferably being such that it may be readily inserted in position across the path of travel of the beam of radiation projected from the source to the radiation sensitive means to intercept the same before reaching the said radiation sensitive means.

By previous calibration of these said plates or sections in a laboratory or other location under known conditions, each said plate or section may be identified as being representative of a known or determined smoke density and as being representative of a known or determined carbon dioxide percentage.

Byutilizing this invention, the furnace operator before starting up the furnace or fire box has only to decide within which range of smoke density or carbon dioxide percentages furnace operation is desired and to adjust his indicator device to this range by the insertion of the required plates in position for a sufficient time interval to set the indicator device to operate within the desired range. Subsequent furnace operation will be regulated in accordance with the settings thereby obtained.

In the drawing, Fig. 1 illustrates in section a typical installation of smoke indicator device;

Fig. 2 is a side elevational view, partly in section; Fig. 8 illustrates one specific embodiment of the present invention; Fig. 4 illustrates a second specific embodiment; and Fig. 5 illustrates a third specific embodiment of the same.

to the drawing, Fla. 1. a typicalinstallation ofia smoke indicator device comprises a source 8 of iradiation, a radiation sensitive device substantially as indicated to sustain-"the source S and device R adjacent aligned openings O- -O' in opposite side walls of flue F but in spaced relation to the side walls so that air vent openings A-A' are provided to prevent smoke dust and condensates from passing from the due into said devices 8 and R. Y The specific structure of devices 8 and R forms no part of the present invention and accordingly,

being well known in the art, need not be ciiically described. However, in Fig, 1 I have shown diagrammatically a lamp B and a lens C and in Fig. 2 I have shown diagrammatically a lens D and a radiation sensitive device E for purposes of illustration. The radiation sensitive device E is electrically connected in an electrical circuit ll energized by current from source I, including an electro-responsive device such as visual indicator II and an adjustable means I! for controlling the energization of external electric control circuits Ila-lib at determined maximum and minimum intensities of the electrical current fiowing in circuit II. The precise arrangement of the elements comprising the means II, II, It, Ila-lib and I4, forms no part of the present invention and is well known in the art and accordingly need not be more specifically described.

In accordance with the present invention, the intensity of the beam of radiation L passing from source S to device R is altered a determined degree by interposing plate P, preferably in the of known or determined density or translucency adapted to intercept a known or determined Per- 75 beam of radiation failing on the said radiation centage of the radiation L representative of that intercepted by fiue gases of equivalent density and of known or calibrated carbon dioxide content indicative of a determined combustion condition within the furnace or fire box connected with the fine.

As illustrated in Fig. 3, the plate P may be comprised of a plurality of sections l to 5 inclusive, each section having a different density or translucency. Plate P, for example, may be comprised of glass having one surface frosted, the degree of frosting on each section varying a determined amount to give a desired range of densities. Alternatively, the glass plate P may be smoked or otherwise colored exteriorly or interiorly to obtain this same result. As a third alternative, the transiucency of the glass may be altered by incorporating therein any desired opaquing material to obtain the same result.

As a second specific embodiment (Fig. 4) plate P may be comprised of screen material, the screen mesh being varied in each section I-I to obtain the desired range of percentage of radiation interruption, substantially as indicated.

As a third specific embodiment (Fig. 5) the plate P" may be comprised of perforated strip material with the number of perforations varying in each section l-! to obtain a desired range of percentage of radiation interruption, substantially as indicated.

It is believed apparent that the density of each section i-! of plate P, P and P" may be calibrated with respect to an equivalent density of flue gases causing an equivalent interruption of radiation and with respect to the known carbon 'dioxide content of such gases and may be standardized in this respect under laboratory control conditions with any given fuel supply to the furnace or fire box, such as oil, coal, pulverized fuel ;etc.. and whenso calibrated and standardized may be employed as a substitute for more expensive and intricate methods of calibration now in use. In small unit installations this is a marked advantage.

Having broadly and specifically disclosed the present invention and; given three specific embodiments of the same, it is apparent that many modifications and adaptations of the same may be made without essential departure therefrom and all such modifications and adaptations are contemplated as may fall within the scope of the accompanying claims,

What I claim is:

1. In smoke indicator devices comprising a radiation sensitive means, a source of radiation of substantially constant intensity, means sustaining the said radiation sensitive means and the said source of radiation adjacent aligned openings in opposite sides of a smoke fiue and an electrical circuit including said radiation sensitive means, a source of electrical energy. and an adjustable means for controlling the energization of external electric control circuits at determined maximum and minimum limits of current intensities in said electrical circuit, the method of obtaining desired adjustment of said adjustable means which". comprises reducing the intensity of the beam of radiation falling on said radiation sensitive device to that approximating the intensity produced by the maximum permissible smoke density in the flue, adiusting the said adjustable means to be actuated by the electrical energy thereby induced in said radiation sensitive device, reducing the intensity of said sensitive device to that approximating the intensity produced by the minimum permissible smoke density in the flue and adjusting the said adjustable means to be actuated by the electrical energy thereby induced in the said radiation sensitive device, and then restoring the intensity of the said beam of radiation to its original intensity and maintaining the same substantially constant during the passage oi smoke gases through the said flue.

2. The method or claim 1 wherein the reduction of the intensity or said beam or radiation to the maximum and minimum intensities respectively is obtained by inserting in radiation interrupting position between the radiation sensitive device and said source radiation at least two radiation permeable members having respectively a density approximating the permissible maximum and minimum densities of the column 01' smoke normally present in said flue.

3. The method or claim 1 wherein the reduction of 'the intensity of said beam of radiation to the maximum and minimum intensities respectively is obtained by inserting in radiation interrupting position between the radiation sensitive device and the said source of radiation, 9. radiation permeable member comprised of glass, the density and radiation absorbing properties of said glass approximating that representative oi the column or smoke in said flue at maximum and minimum densities respectively.

4. The method of claim 1 wherein the reduction or the intensity 01 said beam or radiation is made to be that representative oi. desired maximum and minimum CO2 contents in the smoke gases traversing the said flue.

5. In combination with a smoke detector device including a radiation emitting device and a radiation sensitive device and means sustaining the two said devices opposite aligned openings in a flue with the said radiation sensitive device a predetermined setting of said adjustable means,

said means comprising a plurality of filter memelectrically connected in an electric circuit ineluding a source of electrical energy and an adjustable meansfor controlling the energization of external electric control circuits at determined maximum and minimum limits or current intensities in said electrical circuit, a means to obtain bers each of a diflerent radiation interrupting characteristic with the plurality of said filter members comprising a graduated range oi radiation interrupting characteristics representative 0! determined smoke densities and C0: content ranges and covering the range or adJustment of said adjustable means and means to position said members successively in radiation interrupting position between said radiation sensitive device and said radiation emitting device thereby to artificially induce in said radiation sensitive device the electrical response representative oi the degree of radiation interruption characteristic oi the said member.

6. In combination with a smoke detector device including a source or radiation, 9. radiation sensitive device disposed relative to said source of radiation to be energized thereby, means to pass continuously a column or smoke in radiation interrupting position between said radiation sensitive device and said source or radiation, and

an electrical circuit including said radiation sensitive device, a source or electrical energy and an adjustable means for controlling the energization or external electric control circuits at determined maximum and minimum current intensities in said electrical circuit, means to obtain a presetting 01' said adjustable means to maximum and minimum settings representative or desired maximum and minimum smoke densities, said means comprising a plurality or radiation permeable members each with a different and known density approximating that of the column of smoke at different C02 contents, the plurality of members covering a range 01' smoke densities, and means to dispose any one of said members in radiation interrupting position-between the radiation sensitive device and the said source of radiation in place of said smoke column to simulate in said radiation sensitive device an electric current intensity representative thereof for a time interval at least suilici'ent to obtain an adjustment of said adJustable means.

HENRY 'rnoMss 

